Too Much Folate in Pregnancy Tied to Raised Autism Risk

WEDNESDAY, May 11, 2016 (HealthDay News) -- A new study suggests that excessive amounts of folate and vitamin B12 in a mother's body might increase an infant's risk of developing an autism spectrum disorder. The study findings are scheduled for presentation at the International Meeting for Autism Research, held from May 11 to 14 in Baltimore.

Daniele Fallin, Ph.D., a professor at the Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues analyzed data from 1,391 mother-child pairs in the Boston Birth Cohort, a predominantly low-income minority population. The mothers were recruited at the time of their children's birth between 1998 and 2013, and followed for several years. The study included a check of the mothers' blood folate levels within three days of delivery.

The researchers found that one in 10 of the women had what is considered an excess amount of folate, while 6 percent had an excess amount of vitamin B12. Mothers who had very high blood levels of folate at delivery were twice as likely to have a child with autism compared to mothers with normal folate levels. Mothers with excessive B12 levels were three times as likely to have a child with autism. The risk was greatest among mothers who had excess levels of both folate and B12 -- their risk was over 17 times that of a mother with normal levels of both nutrients.

The study also found that women who took folate and B12 supplements three to five times a week were less likely overall to have a child with autism, particularly when they're taken during the first and second trimesters, Fallin told HealthDay. "The new research question before us is to understand the optimal dose," she added.